As a detecting system for detecting whether sales items are correctly packed in a package, there has conventionally been known a detecting system including: sales items memory means for storing sales items in response to information input to a cash register; commodity information memory means for storing a weight of each commodity as well as a weight of a package; sensing means for measuring an overall weight of the package in which the items are packed; and control means for calculating, based on the information stored in the sales items memory means and the information stored in the commodity information memory means, an overall weight of the package in which the items are packed, and for judging whether the sales items are correctly packed in the package based on a comparison between the calculated overall weight and the overall weight measured by the sensing means (see, for example, Patent Literature 1).
As a similar conventional technology, there has also been known an electronic cash register system including: an electronic cash register having a function of calculating the total of registered articles; and a scale for weighing an article, the electronic cash register including: set value storing means for storing a set weight of each article; adding means for adding the set weight of an article each time the article is registered; total weight storing means for storing the weights added by the adding means; and comparing means for comparing the total weight value stored by the total weight storing means and a measured value obtained when all the articles are weighed by the scale (see, for example, Patent Literature 2).